Arduino Blinking LEDs on input

int currentLedId = 0;

int targetLedPowerState = 0;
int currentLedPowerState = 0;

float timer = 0;

void setup() {
  pinMode(7, OUTPUT);
  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);

  Serial.begin(9600);
}


void loop() {
  if (Serial.available() > 0 ) {
    char incoming = Serial.read();
    Serial.flush();
    Serial.println(incoming);

    processIncomingMessage(incoming);
  }

  blink();
}

void blink() {
  timer += 0.01;

  if (timer > 1000) {
    Serial.println("1000/0.01 ticks is out");
    Serial.println("targetLedPowerState: " + String(targetLedPowerState));
    Serial.println("currentLedPowerState: " + String(currentLedPowerState));
    Serial.println("currentLedId: " + String(currentLedId));

    if (targetLedPowerState == 0) {
      turnLedsOff();
    } else if (targetLedPowerState == 1) {
      if (currentLedPowerState == 0) {
        turnLedOn(currentLedId);
        currentLedPowerState = 1;
      } else if (currentLedPowerState == 1) {
        turnLedsOff();
        currentLedPowerState = 0;
      }
    }

    timer = 0;
  }
}

void processIncomingMessage(char message) {
  switch (message) {
    case '0':
      currentLedId = 7;
      targetLedPowerState = 1;
      break;
    case '1':
      currentLedId = 8;
      targetLedPowerState = 1;
      break;
    case '2':
      currentLedId = 9;
      targetLedPowerState = 1;
      break;
    case '3':
      break;
    case 'f':
      currentLedId = 0;
      targetLedPowerState = 0;
      break;
  }
}

void turnLedOn (int ledPin) {
  turnLedsOff();
  digitalWrite(ledPin, 1);
}

void turnLedsOff () {
  digitalWrite(7, 0);
  digitalWrite(8, 0);
  digitalWrite(9, 0);
}